xref: /netbsd-src/sys/netinet/tcp_var.h (revision dc306354b0b29af51801a7632f1e95265a68cd81)
1 /*	$NetBSD: tcp_var.h,v 1.56 1998/12/18 21:38:03 thorpej Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9  * NASA Ames Research Center.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by the NetBSD
22  *	Foundation, Inc. and its contributors.
23  * 4. Neither the name of The NetBSD Foundation nor the names of its
24  *    contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37  * POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 /*
41  * Copyright (c) 1982, 1986, 1993, 1994, 1995
42  *	The Regents of the University of California.  All rights reserved.
43  *
44  * Redistribution and use in source and binary forms, with or without
45  * modification, are permitted provided that the following conditions
46  * are met:
47  * 1. Redistributions of source code must retain the above copyright
48  *    notice, this list of conditions and the following disclaimer.
49  * 2. Redistributions in binary form must reproduce the above copyright
50  *    notice, this list of conditions and the following disclaimer in the
51  *    documentation and/or other materials provided with the distribution.
52  * 3. All advertising materials mentioning features or use of this software
53  *    must display the following acknowledgement:
54  *	This product includes software developed by the University of
55  *	California, Berkeley and its contributors.
56  * 4. Neither the name of the University nor the names of its contributors
57  *    may be used to endorse or promote products derived from this software
58  *    without specific prior written permission.
59  *
60  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
61  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
62  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
63  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
64  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
65  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
66  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
67  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
68  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
69  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
70  * SUCH DAMAGE.
71  *
72  *	@(#)tcp_var.h	8.4 (Berkeley) 5/24/95
73  */
74 
75 #ifndef _NETINET_TCP_VAR_H_
76 #define _NETINET_TCP_VAR_H_
77 
78 /*
79  * Kernel variables for tcp.
80  */
81 
82 /*
83  * Tcp control block, one per tcp; fields:
84  */
85 struct tcpcb {
86 	struct ipqehead segq;		/* sequencing queue */
87 	u_int	t_timer[TCPT_NTIMERS];	/* tcp timers */
88 	short	t_state;		/* state of this connection */
89 	short	t_rxtshift;		/* log(2) of rexmt exp. backoff */
90 	short	t_rxtcur;		/* current retransmit value */
91 	short	t_dupacks;		/* consecutive dup acks recd */
92 	u_short	t_peermss;		/* peer's maximum segment size */
93 	u_short	t_ourmss;		/* our's maximum segment size */
94 	u_short t_segsz;		/* current segment size in use */
95 	char	t_force;		/* 1 if forcing out a byte */
96 	u_short	t_flags;
97 #define	TF_ACKNOW	0x0001		/* ack peer immediately */
98 #define	TF_DELACK	0x0002		/* ack, but try to delay it */
99 #define	TF_NODELAY	0x0004		/* don't delay packets to coalesce */
100 #define	TF_NOOPT	0x0008		/* don't use tcp options */
101 #define	TF_REQ_SCALE	0x0020		/* have/will request window scaling */
102 #define	TF_RCVD_SCALE	0x0040		/* other side has requested scaling */
103 #define	TF_REQ_TSTMP	0x0080		/* have/will request timestamps */
104 #define	TF_RCVD_TSTMP	0x0100		/* a timestamp was received in SYN */
105 #define	TF_SACK_PERMIT	0x0200		/* other side said I could SACK */
106 #define	TF_SYN_REXMT	0x0400		/* rexmit timer fired on SYN */
107 #define	TF_WILL_SACK	0x0800		/* try to use SACK */
108 #define	TF_CANT_TXSACK	0x1000		/* other side said I could not SACK */
109 #define	TF_IGNR_RXSACK	0x2000		/* ignore received SACK blocks */
110 #define	TF_REASSEMBLING	0x4000		/* we're busy reassembling */
111 
112 
113 	struct	tcpiphdr *t_template;	/* skeletal packet for transmit */
114 	struct	inpcb *t_inpcb;		/* back pointer to internet pcb */
115 	LIST_ENTRY(tcpcb) t_delack;	/* delayed ACK queue */
116 /*
117  * The following fields are used as in the protocol specification.
118  * See RFC783, Dec. 1981, page 21.
119  */
120 /* send sequence variables */
121 	tcp_seq	snd_una;		/* send unacknowledged */
122 	tcp_seq	snd_nxt;		/* send next */
123 	tcp_seq	snd_up;			/* send urgent pointer */
124 	tcp_seq	snd_wl1;		/* window update seg seq number */
125 	tcp_seq	snd_wl2;		/* window update seg ack number */
126 	tcp_seq	iss;			/* initial send sequence number */
127 	u_long	snd_wnd;		/* send window */
128 	tcp_seq snd_recover;		/* for use in fast recovery */
129 /* receive sequence variables */
130 	u_long	rcv_wnd;		/* receive window */
131 	tcp_seq	rcv_nxt;		/* receive next */
132 	tcp_seq	rcv_up;			/* receive urgent pointer */
133 	tcp_seq	irs;			/* initial receive sequence number */
134 /*
135  * Additional variables for this implementation.
136  */
137 /* receive variables */
138 	tcp_seq	rcv_adv;		/* advertised window */
139 /* retransmit variables */
140 	tcp_seq	snd_max;		/* highest sequence number sent;
141 					 * used to recognize retransmits
142 					 */
143 /* congestion control (for slow start, source quench, retransmit after loss) */
144 	u_long	snd_cwnd;		/* congestion-controlled window */
145 	u_long	snd_ssthresh;		/* snd_cwnd size threshhold for
146 					 * for slow start exponential to
147 					 * linear switch
148 					 */
149 /*
150  * transmit timing stuff.  See below for scale of srtt and rttvar.
151  * "Variance" is actually smoothed difference.
152  */
153 	short	t_idle;			/* inactivity time */
154 	short	t_rtt;			/* round trip time */
155 	tcp_seq	t_rtseq;		/* sequence number being timed */
156 	short	t_srtt;			/* smoothed round-trip time */
157 	short	t_rttvar;		/* variance in round-trip time */
158 	short	t_rttmin;		/* minimum rtt allowed */
159 	u_long	max_sndwnd;		/* largest window peer has offered */
160 
161 /* out-of-band data */
162 	char	t_oobflags;		/* have some */
163 	char	t_iobc;			/* input character */
164 #define	TCPOOB_HAVEDATA	0x01
165 #define	TCPOOB_HADDATA	0x02
166 	short	t_softerror;		/* possible error not yet reported */
167 
168 /* RFC 1323 variables */
169 	u_char	snd_scale;		/* window scaling for send window */
170 	u_char	rcv_scale;		/* window scaling for recv window */
171 	u_char	request_r_scale;	/* pending window scaling */
172 	u_char	requested_s_scale;
173 	u_int32_t ts_recent;		/* timestamp echo data */
174 	u_int32_t ts_recent_age;	/* when last updated */
175 	tcp_seq	last_ack_sent;
176 
177 /* SACK stuff */
178 	struct ipqehead timeq;		/* time sequenced queue (for SACK) */
179 };
180 
181 #ifdef _KERNEL
182 /*
183  * TCP reassembly queue locks.
184  */
185 static __inline int tcp_reass_lock_try __P((struct tcpcb *))
186 	__attribute__((__unused__));
187 static __inline void tcp_reass_unlock __P((struct tcpcb *))
188 	__attribute__((__unused__));
189 
190 static __inline int
191 tcp_reass_lock_try(tp)
192 	struct tcpcb *tp;
193 {
194 	int s;
195 
196 	s = splimp();
197 	if (tp->t_flags & TF_REASSEMBLING) {
198 		splx(s);
199 		return (0);
200 	}
201 	tp->t_flags |= TF_REASSEMBLING;
202 	splx(s);
203 	return (1);
204 }
205 
206 static __inline void
207 tcp_reass_unlock(tp)
208 	struct tcpcb *tp;
209 {
210 	int s;
211 
212 	s = splimp();
213 	tp->t_flags &= ~TF_REASSEMBLING;
214 	splx(s);
215 }
216 
217 #ifdef DIAGNOSTIC
218 #define	TCP_REASS_LOCK(tp)						\
219 do {									\
220 	if (tcp_reass_lock_try(tp) == 0) {				\
221 		printf("%s:%d: tcpcb %p reass already locked\n",	\
222 		    __FILE__, __LINE__, tp);				\
223 		panic("tcp_reass_lock");				\
224 	}								\
225 } while (0)
226 #define	TCP_REASS_LOCK_CHECK(tp)					\
227 do {									\
228 	if (((tp)->t_flags & TF_REASSEMBLING) == 0) {			\
229 		printf("%s:%d: tcpcb %p reass lock not held\n",		\
230 		    __FILE__, __LINE__, tp);				\
231 		panic("tcp reass lock check");				\
232 	}								\
233 } while (0)
234 #else
235 #define	TCP_REASS_LOCK(tp)	(void) tcp_reass_lock_try((tp))
236 #define	TCP_REASS_LOCK_CHECK(tp) /* nothing */
237 #endif
238 
239 #define	TCP_REASS_UNLOCK(tp)	tcp_reass_unlock((tp))
240 #endif /* _KERNEL */
241 
242 /*
243  * Queue for delayed ACK processing.
244  */
245 LIST_HEAD(tcp_delack_head, tcpcb);
246 #ifdef _KERNEL
247 extern struct tcp_delack_head tcp_delacks;
248 
249 #define	TCP_SET_DELACK(tp) \
250 do { \
251 	if (((tp)->t_flags & TF_DELACK) == 0) { \
252 		(tp)->t_flags |= TF_DELACK; \
253 		LIST_INSERT_HEAD(&tcp_delacks, (tp), t_delack); \
254 	} \
255 } while (0)
256 
257 #define	TCP_CLEAR_DELACK(tp) \
258 do { \
259 	if ((tp)->t_flags & TF_DELACK) { \
260 		(tp)->t_flags &= ~TF_DELACK; \
261 		LIST_REMOVE((tp), t_delack); \
262 	} \
263 } while (0)
264 #endif /* _KERNEL */
265 
266 /*
267  * Handy way of passing around TCP option info.
268  */
269 struct tcp_opt_info {
270 	int		ts_present;
271 	u_int32_t	ts_val;
272 	u_int32_t	ts_ecr;
273 	u_int16_t	maxseg;
274 };
275 
276 /*
277  * Data for the TCP compressed state engine.
278  */
279 struct syn_cache {
280 	TAILQ_ENTRY(syn_cache) sc_queue;
281 	u_int sc_timer;
282 	u_int32_t sc_hash;
283 	struct in_addr sc_src;
284 	struct in_addr sc_dst;
285 	tcp_seq sc_irs;
286 	tcp_seq sc_iss;
287 	u_short sc_rexmt_count;			/* number of times SYN,ACK
288 						   was retransmitted */
289 	u_short sc_flags;
290 
291 #define	SCF_UNREACH		0x0001		/* we've had an unreach error */
292 #define	SCF_TIMESTAMP		0x0002		/* peer will do timestamps */
293 
294 	struct mbuf *sc_ipopts;			/* IP options */
295 	u_int16_t sc_sport;
296 	u_int16_t sc_dport;
297 	u_int16_t sc_peermaxseg;
298 	u_int16_t sc_ourmaxseg;
299 	u_int8_t sc_request_r_scale	: 4,
300 		 sc_requested_s_scale	: 4;
301 };
302 
303 struct syn_cache_head {
304 	TAILQ_HEAD(, syn_cache) sch_queue;	/* time-sorted entries */
305 	LIST_ENTRY(syn_cache_head) sch_headq;	/* non-empty buckets */
306 	u_short sch_length;			/* # entries in bucket */
307 };
308 
309 #define	intotcpcb(ip)	((struct tcpcb *)(ip)->inp_ppcb)
310 #define	sototcpcb(so)	(intotcpcb(sotoinpcb(so)))
311 
312 /*
313  * The smoothed round-trip time and estimated variance
314  * are stored as fixed point numbers scaled by the values below.
315  * For convenience, these scales are also used in smoothing the average
316  * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
317  * With these scales, srtt has 3 bits to the right of the binary point,
318  * and thus an "ALPHA" of 0.875.  rttvar has 2 bits to the right of the
319  * binary point, and is smoothed with an ALPHA of 0.75.
320  */
321 #define	TCP_RTT_SHIFT		3	/* shift for srtt; 3 bits frac. */
322 #define	TCP_RTTVAR_SHIFT	2	/* multiplier for rttvar; 2 bits */
323 
324 /*
325  * The initial retransmission should happen at rtt + 4 * rttvar.
326  * Because of the way we do the smoothing, srtt and rttvar
327  * will each average +1/2 tick of bias.  When we compute
328  * the retransmit timer, we want 1/2 tick of rounding and
329  * 1 extra tick because of +-1/2 tick uncertainty in the
330  * firing of the timer.  The bias will give us exactly the
331  * 1.5 tick we need.  But, because the bias is
332  * statistical, we have to test that we don't drop below
333  * the minimum feasible timer (which is 2 ticks).
334  * This macro assumes that the value of 1<<TCP_RTTVAR_SHIFT
335  * is the same as the multiplier for rttvar.
336  */
337 #define	TCP_REXMTVAL(tp) \
338 	((((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) >> 2)
339 
340 /*
341  * Compute the initial window for slow start.
342  */
343 #define	TCP_INITIAL_WINDOW(iw, segsz) \
344 	(((iw) == 0) ? (min(4 * (segsz), max(2 * (segsz), 4380))) : \
345 	 ((segsz) * (iw)))
346 
347 /*
348  * TCP statistics.
349  * Many of these should be kept per connection,
350  * but that's inconvenient at the moment.
351  */
352 struct	tcpstat {
353 	u_long	tcps_connattempt;	/* connections initiated */
354 	u_long	tcps_accepts;		/* connections accepted */
355 	u_long	tcps_connects;		/* connections established */
356 	u_long	tcps_drops;		/* connections dropped */
357 	u_long	tcps_conndrops;		/* embryonic connections dropped */
358 	u_long	tcps_closed;		/* conn. closed (includes drops) */
359 	u_long	tcps_segstimed;		/* segs where we tried to get rtt */
360 	u_long	tcps_rttupdated;	/* times we succeeded */
361 	u_long	tcps_delack;		/* delayed acks sent */
362 	u_long	tcps_timeoutdrop;	/* conn. dropped in rxmt timeout */
363 	u_long	tcps_rexmttimeo;	/* retransmit timeouts */
364 	u_long	tcps_persisttimeo;	/* persist timeouts */
365 	u_long	tcps_keeptimeo;		/* keepalive timeouts */
366 	u_long	tcps_keepprobe;		/* keepalive probes sent */
367 	u_long	tcps_keepdrops;		/* connections dropped in keepalive */
368 	u_long	tcps_persistdrops;	/* connections dropped in persist */
369 	u_long	tcps_connsdrained;	/* connections drained due to memory
370 					   shortage */
371 
372 	u_long	tcps_sndtotal;		/* total packets sent */
373 	u_long	tcps_sndpack;		/* data packets sent */
374 	u_long	tcps_sndbyte;		/* data bytes sent */
375 	u_long	tcps_sndrexmitpack;	/* data packets retransmitted */
376 	u_long	tcps_sndrexmitbyte;	/* data bytes retransmitted */
377 	u_long	tcps_sndacks;		/* ack-only packets sent */
378 	u_long	tcps_sndprobe;		/* window probes sent */
379 	u_long	tcps_sndurg;		/* packets sent with URG only */
380 	u_long	tcps_sndwinup;		/* window update-only packets sent */
381 	u_long	tcps_sndctrl;		/* control (SYN|FIN|RST) packets sent */
382 
383 	u_long	tcps_rcvtotal;		/* total packets received */
384 	u_long	tcps_rcvpack;		/* packets received in sequence */
385 	u_long	tcps_rcvbyte;		/* bytes received in sequence */
386 	u_long	tcps_rcvbadsum;		/* packets received with ccksum errs */
387 	u_long	tcps_rcvbadoff;		/* packets received with bad offset */
388 	u_long	tcps_rcvmemdrop;	/* packets dropped for lack of memory */
389 	u_long	tcps_rcvshort;		/* packets received too short */
390 	u_long	tcps_rcvduppack;	/* duplicate-only packets received */
391 	u_long	tcps_rcvdupbyte;	/* duplicate-only bytes received */
392 	u_long	tcps_rcvpartduppack;	/* packets with some duplicate data */
393 	u_long	tcps_rcvpartdupbyte;	/* dup. bytes in part-dup. packets */
394 	u_long	tcps_rcvoopack;		/* out-of-order packets received */
395 	u_long	tcps_rcvoobyte;		/* out-of-order bytes received */
396 	u_long	tcps_rcvpackafterwin;	/* packets with data after window */
397 	u_long	tcps_rcvbyteafterwin;	/* bytes rcvd after window */
398 	u_long	tcps_rcvafterclose;	/* packets rcvd after "close" */
399 	u_long	tcps_rcvwinprobe;	/* rcvd window probe packets */
400 	u_long	tcps_rcvdupack;		/* rcvd duplicate acks */
401 	u_long	tcps_rcvacktoomuch;	/* rcvd acks for unsent data */
402 	u_long	tcps_rcvackpack;	/* rcvd ack packets */
403 	u_long	tcps_rcvackbyte;	/* bytes acked by rcvd acks */
404 	u_long	tcps_rcvwinupd;		/* rcvd window update packets */
405 	u_long	tcps_pawsdrop;		/* segments dropped due to PAWS */
406 	u_long	tcps_predack;		/* times hdr predict ok for acks */
407 	u_long	tcps_preddat;		/* times hdr predict ok for data pkts */
408 
409 	u_long	tcps_pcbhashmiss;	/* input packets missing pcb hash */
410 	u_long	tcps_noport;		/* no socket on port */
411 	u_long	tcps_badsyn;		/* received ack for which we have
412 					   no SYN in compressed state */
413 
414 	/* These statistics deal with the SYN cache. */
415 	u_long	tcps_sc_added;		/* # of entries added */
416 	u_long	tcps_sc_completed;	/* # of connections completed */
417 	u_long	tcps_sc_timed_out;	/* # of entries timed out */
418 	u_long	tcps_sc_overflowed;	/* # dropped due to overflow */
419 	u_long	tcps_sc_reset;		/* # dropped due to RST */
420 	u_long	tcps_sc_unreach;	/* # dropped due to ICMP unreach */
421 	u_long	tcps_sc_bucketoverflow;	/* # dropped due to bucket overflow */
422 	u_long	tcps_sc_aborted;	/* # of entries aborted (no mem) */
423 	u_long	tcps_sc_dupesyn;	/* # of duplicate SYNs received */
424 	u_long	tcps_sc_dropped;	/* # of SYNs dropped (no route/mem) */
425 	u_long	tcps_sc_collisions;	/* # of hash collisions */
426 };
427 
428 /*
429  * Names for TCP sysctl objects.
430  */
431 #define	TCPCTL_RFC1323		1	/* RFC1323 timestamps/scaling */
432 #define	TCPCTL_SENDSPACE	2	/* default send buffer */
433 #define	TCPCTL_RECVSPACE	3	/* default recv buffer */
434 #define	TCPCTL_MSSDFLT		4	/* default seg size */
435 #define	TCPCTL_SYN_CACHE_LIMIT	5	/* max size of comp. state engine */
436 #define	TCPCTL_SYN_BUCKET_LIMIT	6	/* max size of hash bucket */
437 #define	TCPCTL_SYN_CACHE_INTER	7	/* interval of comp. state timer */
438 #define	TCPCTL_INIT_WIN		8	/* initial window */
439 #define	TCPCTL_MSS_IFMTU	9	/* mss from interface, not in_maxmtu */
440 #define	TCPCTL_SACK		10	/* RFC2018 selective acknowledgement */
441 #define	TCPCTL_WSCALE		11	/* RFC1323 window scaling */
442 #define	TCPCTL_TSTAMP		12	/* RFC1323 timestamps */
443 #define	TCPCTL_COMPAT_42	13	/* 4.2BSD TCP bug work-arounds */
444 #define	TCPCTL_CWM		14	/* Congestion Window Monitoring */
445 #define	TCPCTL_CWM_BURSTSIZE	15	/* burst size allowed by CWM */
446 #define	TCPCTL_ACK_ON_PUSH	16	/* ACK immediately on PUSH */
447 #define	TCPCTL_KEEPIDLE		17	/* keepalive idle time */
448 #define	TCPCTL_KEEPINTVL	18	/* keepalive probe interval */
449 #define	TCPCTL_KEEPCNT		19	/* keepalive count */
450 #define	TCPCTL_SLOWHZ		20	/* PR_SLOWHZ (read-only) */
451 #define	TCPCTL_NEWRENO		21	/* NewReno Congestion Control */
452 #define	TCPCTL_MAXID		22
453 
454 #define	TCPCTL_NAMES { \
455 	{ 0, 0 }, \
456 	{ "rfc1323",	CTLTYPE_INT }, \
457 	{ "sendspace",	CTLTYPE_INT }, \
458 	{ "recvspace",	CTLTYPE_INT }, \
459 	{ "mssdflt",	CTLTYPE_INT }, \
460 	{ "syn_cache_limit", CTLTYPE_INT }, \
461 	{ "syn_bucket_limit", CTLTYPE_INT }, \
462 	{ "syn_cache_interval", CTLTYPE_INT },\
463 	{ "init_win", CTLTYPE_INT }, \
464 	{ "mss_ifmtu", CTLTYPE_INT }, \
465 	{ "sack", CTLTYPE_INT }, \
466 	{ "win_scale", CTLTYPE_INT }, \
467 	{ "timestamps", CTLTYPE_INT }, \
468 	{ "compat_42", CTLTYPE_INT }, \
469 	{ "cwm", CTLTYPE_INT }, \
470 	{ "cwm_burstsize", CTLTYPE_INT }, \
471 	{ "ack_on_push", CTLTYPE_INT }, \
472 	{ "keepidle",	CTLTYPE_INT }, \
473 	{ "keepintvl",	CTLTYPE_INT }, \
474 	{ "keepcnt",	CTLTYPE_INT }, \
475 	{ "slowhz",	CTLTYPE_INT }, \
476 	{ "newreno",	CTLTYPE_INT }, \
477 }
478 
479 #ifdef _KERNEL
480 struct	inpcbtable tcbtable;	/* head of queue of active tcpcb's */
481 struct	tcpstat tcpstat;	/* tcp statistics */
482 u_int32_t tcp_now;		/* for RFC 1323 timestamps */
483 extern	int tcp_do_rfc1323;	/* enabled/disabled? */
484 extern	int tcp_do_sack;	/* SACK enabled/disabled? */
485 extern	int tcp_do_win_scale;	/* RFC1323 window scaling enabled/disabled? */
486 extern	int tcp_do_timestamps;	/* RFC1323 timestamps enabled/disabled? */
487 extern	int tcp_do_newreno;	/* Use the New Reno algorithms */
488 extern	int tcp_mssdflt;	/* default seg size */
489 extern	int tcp_init_win;	/* initial window */
490 extern	int tcp_mss_ifmtu;	/* take MSS from interface, not in_maxmtu */
491 extern	int tcp_compat_42;	/* work around ancient broken TCP peers */
492 extern	int tcp_cwm;		/* enable Congestion Window Monitoring */
493 extern	int tcp_cwm_burstsize;	/* burst size allowed by CWM */
494 extern	int tcp_ack_on_push;	/* ACK immediately on PUSH */
495 extern	int tcp_syn_cache_limit; /* max entries for compressed state engine */
496 extern	int tcp_syn_bucket_limit;/* max entries per hash bucket */
497 extern	int tcp_syn_cache_interval; /* compressed state timer */
498 
499 extern	int tcp_syn_cache_size;
500 extern	int tcp_syn_cache_timeo;
501 extern	struct syn_cache_head tcp_syn_cache[];
502 extern	u_long syn_cache_count;
503 
504 #define	TCPCTL_VARIABLES { \
505 	{ 0 },					\
506 	{ 1, 0, &tcp_do_rfc1323 },		\
507 	{ 1, 0, &tcp_sendspace },		\
508 	{ 1, 0, &tcp_recvspace },		\
509 	{ 1, 0, &tcp_mssdflt },			\
510 	{ 1, 0, &tcp_syn_cache_limit },		\
511 	{ 1, 0, &tcp_syn_bucket_limit },	\
512 	{ 1, 0, &tcp_syn_cache_interval },	\
513 	{ 1, 0, &tcp_init_win },		\
514 	{ 1, 0, &tcp_mss_ifmtu },		\
515 	{ 1, 0, &tcp_do_sack },			\
516 	{ 1, 0, &tcp_do_win_scale },		\
517 	{ 1, 0, &tcp_do_timestamps },		\
518 	{ 1, 0, &tcp_compat_42 },		\
519 	{ 1, 0, &tcp_cwm },			\
520 	{ 1, 0, &tcp_cwm_burstsize },		\
521 	{ 1, 0, &tcp_ack_on_push },		\
522 	{ 1, 0, &tcp_keepidle },		\
523 	{ 1, 0, &tcp_keepintvl },		\
524 	{ 1, 0, &tcp_keepcnt },			\
525 	{ 1, 1, 0, PR_SLOWHZ },			\
526 	{ 1, 0, &tcp_do_newreno },		\
527 }
528 
529 int	 tcp_attach __P((struct socket *));
530 void	 tcp_canceltimers __P((struct tcpcb *));
531 struct tcpcb *
532 	 tcp_close __P((struct tcpcb *));
533 void	 *tcp_ctlinput __P((int, struct sockaddr *, void *));
534 int	 tcp_ctloutput __P((int, struct socket *, int, int, struct mbuf **));
535 struct tcpcb *
536 	 tcp_disconnect __P((struct tcpcb *));
537 struct tcpcb *
538 	 tcp_drop __P((struct tcpcb *, int));
539 void	 tcp_dooptions __P((struct tcpcb *,
540 	    u_char *, int, struct tcpiphdr *, struct tcp_opt_info *));
541 void	 tcp_drain __P((void));
542 void	 tcp_established __P((struct tcpcb *));
543 void	 tcp_fasttimo __P((void));
544 void	 tcp_init __P((void));
545 void	 tcp_input __P((struct mbuf *, ...));
546 u_long	 tcp_mss_to_advertise __P((const struct ifnet *));
547 void	 tcp_mss_from_peer __P((struct tcpcb *, int));
548 void	 tcp_mtudisc __P((struct inpcb *, int));
549 struct tcpcb *
550 	 tcp_newtcpcb __P((struct inpcb *));
551 void	 tcp_notify __P((struct inpcb *, int));
552 u_int	 tcp_optlen __P((struct tcpcb *));
553 int	 tcp_output __P((struct tcpcb *));
554 void	 tcp_pulloutofband __P((struct socket *,
555 	    struct tcpiphdr *, struct mbuf *));
556 void	 tcp_quench __P((struct inpcb *, int));
557 int	 tcp_reass __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *));
558 int	 tcp_respond __P((struct tcpcb *,
559 	    struct tcpiphdr *, struct mbuf *, tcp_seq, tcp_seq, int));
560 void	 tcp_rmx_rtt __P((struct tcpcb *));
561 void	 tcp_setpersist __P((struct tcpcb *));
562 void	 tcp_slowtimo __P((void));
563 struct tcpiphdr *
564 	 tcp_template __P((struct tcpcb *));
565 struct tcpcb *
566 	 tcp_timers __P((struct tcpcb *, int));
567 void	 tcp_trace __P((int, int, struct tcpcb *, struct tcpiphdr *, int));
568 struct tcpcb *
569 	 tcp_usrclosed __P((struct tcpcb *));
570 int	 tcp_sysctl __P((int *, u_int, void *, size_t *, void *, size_t));
571 int	 tcp_usrreq __P((struct socket *,
572 	    int, struct mbuf *, struct mbuf *, struct mbuf *, struct proc *));
573 void	 tcp_xmit_timer __P((struct tcpcb *, int));
574 tcp_seq  tcp_new_iss __P((void *, u_long, tcp_seq));
575 
576 int	 syn_cache_add __P((struct socket *, struct mbuf *, u_char *,
577 	    int, struct tcp_opt_info *));
578 void	 syn_cache_unreach __P((struct ip *, struct tcphdr *));
579 struct socket *
580 	 syn_cache_get __P((struct socket *so, struct mbuf *));
581 void	 syn_cache_init __P((void));
582 void	 syn_cache_insert __P((struct syn_cache *));
583 struct syn_cache *
584 	 syn_cache_lookup __P((struct tcpiphdr *, struct syn_cache_head **));
585 void	 syn_cache_reset __P((struct tcpiphdr *));
586 int	 syn_cache_respond __P((struct syn_cache *, struct mbuf *,
587 	    register struct tcpiphdr *, long, u_long));
588 void	 syn_cache_timer __P((void));
589 
590 int	tcp_newreno __P((struct tcpcb *, struct tcpiphdr *));
591 #endif
592 
593 #endif /* _NETINET_TCP_VAR_H_ */
594